There is a limitation of the size of hand luggage, as per the IATA standard (56cm x 40cm x 25cm). If you exceed this limitation, the staff at security control will direct you to the check-in desks and you will have to check in your luggage.
Your jacket or coat has to pass through the X-ray at security control separately from your hand luggage, while you pass through the metal detector arch.
Your laptop and any large electrical or electronic device will also have to pass through the X-ray separately from your other hand luggage.
If you are flying from the USA, Dominican Republic or Costa Rica, the maximum amount of powder-based substances that you can take in your hand luggage is 12oz/350ml/350g.